If you got your 50$ from pokerstrategy on titan and registered with the PS150 bonuscode you won't be able to get a first deposit bonus. But you can still use one of the reload bonuses titan is regulary offering.
If you have further questions you can take a look in the Titan Poker FAQ .

Yet at the moment the summer time bonus is active - which is essentially an unlimited bonus of 10$ for every 25$ rake, so reloads and first deposits aren't really necessary.